Modern vehicles typically have one or more diagnostic systems, generally having separate computer control modules to control various functions of the vehicle. Some examples include a powertrain control module (PCM), an engine control module (ECM), a transmission control module (TCM), an anti-locking brake system (ABS), and an air bag control module. The vehicle diagnostic systems often have self-diagnostic capabilities to detect and alert the driver of problems that the vehicle may be encountering. When a problem is found, a diagnostic trouble code (DTC), is set within the computer's memory. DTCs are as general or as specific as the manufacturer desires.
To retrieve and decipher DTCs, an auto repair technician needs a diagnostic tool, such as a scan tool. The scan tool is connected to the vehicle's computer bus system via a data link connector (DLC) to access and retrieve the DTCs. Scan tools are testing devices that interface with vehicle diagnostic systems to retrieve information from the various control modules. Scan tools are equipped to communicate in various communication protocols such as Controller Area Network (CAN), J1850 VPM and PWM, ISO 9141, Keyword 2000 and others. These communication protocols may be specific to each of the various vehicle manufacturers. The scan tool will help the technician to diagnose and repair the vehicle based on the information the tool retrieves from the vehicle.
Further, the technician during testing may take the vehicle for a drive and may inadvertently speed or leave a defined testing area. Accordingly, it is desirable to provide alerts to the technician when certain events occur.